Detect the end of a HTTP packet

Question

I have to write a PHP script that works as a client against another HTTP Server. This Server ignores the HTTP Connection:Close header and keeps the TCP connection open unless it is closed by the client. And here is my dilemma. I (the client) have to deciede when a HTTP request/response has finished and then close the connection. Simply use:

$data = file_get_contents($url);

.. won't work, as file_get_contents returns only if the connection timeout (default 30 seconds) has reached.

So I have to write my own read - loop like this (pseudo code):

$sock = fsockopen(...);
$data = '';
while($line = fgets($sock)) {
    $data .= $line;
    if(http_package_recieved()) {
        break;
    }
}

Unfortunately there is no Content-Length header in the response. My question is, how the function

http_package_recieved()

... should look like.

Greets Thorsten

The question was downvoted today - 5 years after having posted. Can the downvoter explain the reasoning behind that? — hek2mgl, Jun 10 '15 at 12:32

score 3 · Answer 1 · answered Sep 15 '10 at 13:52

You can check if $line is empty to see if the server isn't sending anything. You can also set a small read timeout on the socket with stream_set_timeout() , and then inside the loop check stream_get_meta_data() to see if it has been reached in order to break out.

score 2 · Answer 2 · edited Oct 07 '21 at 06:06

2

You'd be better of using a library, such as cURL (http://uk.php.net/manual/en/intro.curl.php), to handle this. The HTTP spec isn't simple: https://www.rfc-editor.org/rfc/rfc2616 (see Section 4.4) and you'd likely miss something crucial.

edited Oct 07 '21 at 06:06

Community

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answered Sep 15 '10 at 13:44

Rushyo

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score 2 · Accepted Answer · answered Sep 15 '10 at 13:48

2

If it doesn't close the connection and it doesn't tell you the total length of the response, you have no way to know whether all the data has been received.

You could specify a maximum time interval between packets, but that won't be reliable.

answered Sep 15 '10 at 13:48

Artefacto

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You can, if it's using HTTP Chunked Transfer Encoding. – Bruno Sep 15 '10 at 13:49
@Bruno That's true. It remains to be seen if that's the case (the OP doesn't specify it). – Artefacto Sep 15 '10 at 13:50
@Bruno: That's a big *if*. However, unless the server specifies this or Content-length and doesn't close the connection, there's indeed no way to tell (shouldn't happen, but apparently can). – Piskvor left the building Sep 15 '10 at 13:59
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I'll read about Transfer-Encoding: chunked and tell my success (or not ;) ) – hek2mgl Sep 15 '10 at 14:08

score 1 · Answer 4 · answered Sep 15 '10 at 13:47

1

When the entity ends is either guided by:

Content-Length header (which you don't have)
HTTP Chunked Transfer Encoding (see Transfer-Encoding: chunked header: do you have one of these?).

It's possible you may have to process this chunked transfer encoding if you get this header. There are libraries to do so.

answered Sep 15 '10 at 13:47

Bruno

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Transfer-Encoding: chunked, I *have*. I'll read about this. thanks. – hek2mgl Sep 15 '10 at 14:06
I'd strongly recommend using a library to do so, unless you have a good reason not to. libcurl is available via PHP (as @Rushyo said). – Bruno Sep 15 '10 at 14:09

score 0 · Answer 5 · answered Sep 15 '10 at 13:45

0

feof($sock) would be OK

answered Sep 15 '10 at 13:45

baton

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Detect the end of a HTTP packet

5 Answers5

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